Icu Update Activity Message

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds context annotations cannot: that the old text is not recoverable otherwise, that the tool returns both old and new text as a safety net, and that edits are restricted to the caller's own notes. This is exactly the supplemental disclosure expected alongside annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The destructive, irreplaceable nature is front-loaded in the first line, followed by usage examples and then the sibling exclusion. Every sentence carries distinct information; nothing is padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive 3-parameter mutation, the description covers irreversibility, ownership constraints, the semantic difference from the add-sibling, and the return payload; the output schema handles return-value details. Nothing an agent needs before calling it is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the schema already explains that content 'replaces the old text entirely' and that message_id comes from icu_get_activity_messages. The description repeats the replacement semantics but adds no new parameter-level detail, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence gives a specific verb (REPLACE) and resource (the text of an existing note on an activity) and immediately disambiguates with '(edit, not add)'. An agent can distinguish it from icu_add_activity_message without inspecting either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It names concrete trigger utterances ('correct my note on that ride', 'change the comment to say...'), states the exclusion and the correct alternative ('To post an additional note use icu_add_activity_message'), and adds a precondition (only the author's own notes can be changed).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.